Arrangement of a connecting rod on a crankshaft



Jan. 5, 1965 E. HATz, JR.. ETAL 3,164,423

ARRANGEMENT oF A CONNECTING Ron oN A cR/mxsmuvrv 2 Sheets-Sheet 1 Filed May 1, 1963 Num.

Jan. 5, 1965 E. HATz, JR.. ETAL 3,164,423

ARRANGEMENT 0F A CONNECTING ROD ON A CRANKSHAFT 2 Sheets-Sheet 2 Filed May 1, 1963 m, .mi

l1 mm United States Patent O "i 3,164,423 ARRANGEMENT "F A CQNNECTING R01) 0N A CRANKSl-IAFT Ernst Hatz, Jr., and Karl Heinz Neuer, Ruhstorf, naar Passau, and Wilfried Rein, llgiharting, near Munich, Germany, assignors to Motorenfabrilr Hatz G.m.b.H., Passau, Germany, a corporation of Germany Filed May l, 1963 Ser. No. 277,364 Claims priority, application Germany, May 21,'

1962, M 52,9341 4 Claims. (Cl. 308-207) This invention relates to an arrangement of a connecting rod on a crank pin of a crankshaft wherein roller bodies, accommodated in a cage, are interposed between the said rod and the crank pin.

In known arrangements of this type 'the connecting rod or the crankshaft is frequently composed of two parts which, after they have been assembled and thevzr'oller bodies introduced into the cage, are firmly connected by a plurality of screws. These screws, and flanges which receive them, however, greatly enlarge the working circle and path of movement of the connecting rod and the crankshaft. Therefore the dimensions of the crankcase must also be made commensurately large. Such a two- -part construction of the components has the additional disadvantage of involving increased fabrication and assembly costs, and an increaserin the inertial mass to be displaced. l

-The primary object of the present invention is to provide an improved larrangement in which both the crankshaft vand the connecting rod can each bel made in one piece and the roller cage canV also consist of a unitary fabrication.

Another aim is to provide such an' arrangement which can be installed in a comparatively small space, and produced at low manufacturing costs. 'The improved arrangement,constituting this invention is characterized in thatl with the components assembled iny their working positions, the big end of the connecting rod and the cage for the roller bodies are applied, for the purpose of lateral Vguidance at least atvone side of the said rod, against a fillet which is of a thickness'corresponding approximately to the length of a roller body and is detachably connected to the crankshaft. The crank pin, in axial length, is longer than the actual bearing width by an amount approximately equal tothe axial length of one roller body. With the fillet removed, the roller body cage can be moved axially by that amount so that it can be filled with rollerbodies. After being filled, the cage is moved back and the llet inserted.

In accordance with a further and advantageous feature ofy the invention theiillet may be detachably connected to the inner side of the relevant crank arm of the connecting rod by means of a screw and in such a manner that it partially surrounds the crank pin, the screw being arranged in an axial bore in the journal pin of the crankshaft and engaging in a tapped opening in the fillet. This allows for detachable connection of the fillet to the crankshaft by very simple means.

To provide for easy insertion of roller bodies into the bearing space between the connecting rod, the cage and the crank pin, an opening for such insertion may, according to yet another feature of the invention, be provided in the side of the big end facing the fillet.

In order that the invention may be more clearly understood and readily carried into practical effect, one specific example thereof will-now be described with reference to the accompanying drawings, wherein,

FIGURE lv shows, partly in outside elevation and partly in longitudinallsection, a fully assembled crankshaft, connecting rod and bearing arrangement according to this invention, l

` hand crank arm lb is .displaced by this amount, laterally LAZ Patented Jan. 5, 1965 FIGURE 2 is a cross-sectional View of the bearing arrangement taken on the line lll-ll of FIGURE 1, and

FIGURE 3 is a view corresponding and similar to the central portion of FIGURE l but showing the insertion of roller bodies int-o the cage during assembly of the a1'- rangement. Like parts are designated by similar reference characters throughout the drawings.

The invention is illustrated, by way of example, as applied to the crankshaft of a single cylinder internal combustion engine. The one-piece crankshaft l, of cast steel, has two co-axialv journal bearings la, lau, in the usual way, and two axially spaced and radially offset crank-arms lb, lbb which are connected by a crank pin lc. Mounted upon this crank pin is the closed big end 2a of a one-piece connecting rod Z, also'made of cast steel, which in tum is yconnected to the piston (not shown) of the internal `combustion engine. yThe bearing of the big end 2a upon the crank pin 1c is effected through the mediumv of interposed roller bodies. In the illustrated example, these bodies consist of cylindrical rollers 3 arranged in three side-by-side circular series each comprising fourteen rollers. Therollers are housed in aY unitary cage d made of light metal and having fourteen axially extending parallel guideslots da (see FIGURES` 2 and 3), each adapted to accommodate three side-byside rollers 3. The case itself is mounted for rotation freely within the borein the big end 2a of the connecting rod. To make such a bearing arrangement feasible when t-he aforementioned components iare of one-piece construction, `the following expedients are adopted in accordance with the present invention The axial width of the big end 2a is the same as that of the cage 4. The crank pin lc is made of afwidth greater than that which is actually required for supporting the rollers 3, by an amount corresponding to the length of any one of the latter. As illustrated, the right of the crank pin lc, to enable afiat fillet 5 to be introduced between the1said crank arm anditherbig end 2a, adjacent .to the periphery of the lcrank pin lc. This fillet has a plane end face 5a which holds the connecting rodl 2 and the roller cage 4 against lateral displacement in one axial direction. These components Z and 4 are held-from movement axially in the opposite direction-by the lateral guide surface lbb of the opposite crank arm lbb. The inner diameter of the cage 4 and its axial width, on the one hand, and the diameter and curvature of the crank arm 1b on the other hand, lareso related to one another that Vthe big end 2a, with an empty cage d inserted therein, can be slipped over the crankshaft parts la, lb and on to' the crank-pin lc. v v

The fillet Siis detachably secured to the inner side of the crank'arm 1b .by means of a screw 6 which is arranged in an axial bore la of the 'crankshaft bearing pinv Y 'la and has a threaded end 6a screwed' into a tapped hole A lateral hole la" in the outer /end of the bearing pin la provides for the introduction andy 5b in the said fillet.'

tightening up on the screw 6 during assembly. The llet 5 is so formed that'it will engage in horseshoe fashion `around the crank pin lc' and is thereby prevented from 2b, apparent in FIGURE 2, is a little in excess of the n diameter ofthe individual rollers 3.

*ff V1.."i`he combinationy comprising The steps of assembling the connecting rod upon the crankshaft are as follows:

The big end 2a, with an empty cage 4 inserted therein, is rst slipped over the crankshaft parts la, lb and on to the crank pin lc. The big end 2a is then held against the lateral guide face lbb' of the left hand crank arm lbb, while the cage4 is shifted to the right within the bore in the big end and towards the crank arm 1b, as clearly seen in FlGURE 3.V A passageway is .thereby provided between the right hand bounding edge of a relevant cage lslot 4a and the left hand bounding edge of the filling opening 2b, and the three rollers for each guide slot in the case are introduced individually and in' succession throughthis pass-age. Eachiroller is, in fact, first introduced radially inthe direction of. the arrow A (FIGURE 3) and is then, it" necessary, moved axially to the left infthe direction of the. arrov B, until has reached its working position. Aftery three rollers 3 have been inserted `in any one slot in the y,case 4 is thereupon turned through an angularV extent corresponding to one pantition so as to bring theV next empty slot-dez into the required position opposite to, the filling opening 2b for' the introduction thereinto of the next three rol-1ers. This filling-operation is repeated fourteen times, in the speciiic example now being described, until all the-slots 4a have been filled-each by a set of three rollers 3.

, Thereafter the lledV cage 4 isy shifted back leftwards from lthe position illustrated in FTGURE 3 into that depicted in FIGURE 1.and is retained in this working .position by the introduction and tightening up of Vthe llet 5. This completes the mounting of the components 1 and VZ-w'ith the roller bodies, 3 accommodated in the l cage 4 in position between them.

The arrangement according to the .invention provides many advantages; Inthe first place it enables the components-to Vbe made as one-piece members, and this reduces "the manufacturing costs. Moreover, the lightweight'"constructionof the' component parts improves the performance of the internal combustion engine. lIn addition the assembly is simple and Vcan be performed quickly without necessitating auxiliary tools. Thus, the k improved arrangement isarational and economic one. Theouter diameterfof the big end and the throw of the crankshaft can, by Virtue ofthe omission of the clamping screws which have hitherto been used on the connecting rod and the crankshaft, be madev substantially smaller and Vthis in turn results' in Va `more compact construction ofthe crank lcase and consequently of lthe 'engine itself. A Finally, it is to ybe clearly understood that the construction herein specitically described represents only one Vofthe potential v'forms of the improved arrangement accordingV to the present invention. Thus,` for example, the invention may be employed with equal advantage'in each sideof the big end of eachconnecting'rod.

' What we claimlis: 'Y

a unitary'crankshaft having at least one radially otfset crankpin, a unitary connecting rodv journalled at 'its lbig end to said crankpin,

said bigf'end having aninternal cylindrical bearing surface andhaving roller bodies tted in 'a unitary cage movably disposedin said internal cylindrical bearing surface, said unitary cage comprising a unitary tube having a collar at either'endand slots disposed between said collars to retain said roller bodies, said unitary cage further having an Iaxial length substantially corresponding to the axial length of said big end, each crankpin being axially longer than the axial length of cylindrical bearing surface by a distance approximately equal to the axial length of one of said roller bodies, and at least one fillet having a thickness substantially equal to the length of one of said roller bodies and being detachably connected to said crankshaft bearing against and holding in position the cage and the big end of the connecting rod on said crankpin of the crankshaft.

2. The combination according to claim l wherein said big end of the connecting rod has a radial slot at one of its edges communicating with said internal bearing surface, said slot being substantially equal in an axial direction to the Width of said collar and being substantially equal in circumferential width to the diameter of a roller body. Y 3. The combination as set lorth in claim 2 wherein said fillet is aligned with the main longitudinal axis of said crankshaft, further comprising a longitudinally extending passage forrned in said crankshaft substantially along the longitudinal axis thereof, and a screwthreaded member in said longitudinal passage for detachably holding said iillet in position so as to maintain said cage and said big end in position and so as to be removable to permit said cage to be displaced longitudinally for a distance suiicient to clear said slot for insertion or removal of said roller bodies.

4. A combination comprising a unitary crank having at least one radially odset crankpin section having a cylindrical bearing surface, 4a connecting rod journalled to said bearing surface by means of roller bodies disposed in a cage removably fitted within an internal bearing surface in said connecting rod, said cage comprising .a unitary tubular member having collars at either end and axial slots, each slot containing a plurality of roller bodies, the diameter of said roller bodies being appreciably greater than the Wall thickness of said tubular cage, said crankpin section being longer in axial direction than the axial length of said connecting rod by a distance substantially equal to the length of one of said roller bodies so as to permit axial movement of said cage, a slot in an edge of said connecting rod communicating with said internal bearing surface, said slot in an edge of said connecting rod being of a size permitting one of said roller bodies to be inserted therethrough when said cage is shifted axially and being substantially covered by one of said collars when said cage is in its normal position, and at least one llet detachably connected by screw means to said crankshaft and disposed between said crankshaft and said connecting rod to hold said connecting rod and said cage in position over said cylindrical bearing' surface of said crankpin section.

References Cited by the Examiner UNiTE J STATES PATENTS 1,383,292 7/21 Douglas 308-4179 1,479,324 1/24 Schneider 308-179 1,963,407 6/34 Herrmann BGS-217 2,248,615 7/4l Frauenthal 308-207 2,695,204 lil/54 Matera 308--179 FOR ElGN PATENTS 611,4l9 7/26 France. 122,559 l/l9 Great Britain.

FRANK SUSKO, Primary Examiner.

ROBERT C. RlRDON, Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE 0F CORRECTION Patent No. 3,164,425 January 5, 1965 Ernst Hatz, Jr., et a1.

1t is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below In the grant, line 4, for "of Passau, Germany," read of Ruhstrf, near Passau, Germany, in the heading to the printed specification, line 7, for "Passau, Germany," read Ruhstorf, near Passau, Germany,

Signed and sealed this 29th day of June 1965.

(SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents ERNEST W. SWIDER Aitesting Officer 

1. THE COMBINATION COMPRISING A UNITARY CRANKSHAFT HAVING AT LEAST ONE RADIALLY OFFSET CRANKPIN, A UNITARY CONNECTING ROD JOURNALLED AT ITS BIG END TO SAID CRANKPIN, SAID BIG END HAVING AN INTERNAL CYLINDRICAL BEARING SURFACE AND HAVING ROLLER BODIES FITTED IN A UNITARY CAGE MOVABLY DISPOSED IN SAID INTERNAL CYLINDRICAL BEARING SURFACES, SAID UNITARY CAGE COMPRISING A UNITARY TUBE HAVING A COLLAR AT EITHER END AND SLOTS DISPOSED BETWEEN SAID COLLARS TO RETAIN SAID ROLLER BODIES, SAID UNITARY CAGE FURTHER HAVING AN AXIAL LENGTH SUBSTANTIALLY CORRESPONDING TO THE AXIAL LENGTH OF SAID BIG END, EACH CRANKPIN BEING AXIALLY LONGER 